MICROBIAL GENETICS CH 6 Flashcards
Define Genetics
The study of inheritance or heredity that explores the expression and transfer of genes and traits
Define Genome
The total of genetic material of an organism consisting of that found in:
- Nucleus/Nucleoid Region
- Plasmid
- Mitochondrial/Chloroplast DNA
Define Gene
A segment of DNA that codes for a functional protein or RNA product
Define Chromosome
Neatly Packaged nucleic acid molecule
Define Genomics
The study of an organisms entire genome
Primary difference between prokaryotic and eukaryotic DNA
Prok - Circular
Euk - Linear
What are the three categories in which genes function
- Proteins
- Regulatory genes that control gene expression
- RNA machinery
Genotype vs Phenotype
Genotype - Genetic Information
Phenotype - Physical, observable traits
What is a nucleotide? Describe the basic components
Basic unit of DNA composed of
- Sugar
- Phosphate Group
- Nitrogeous Base/Base Pair (A-T, C-G)
What bond type is found in DNA
Hydrogen Bonds
What composes the backbone of DNA?
Deoxyribose and Phosphate
What is the arrangement of DNA
Antiparallel; one strand runs in the 5’>3’ direction and the other in the opposite
- Phosphate Group is the 5’ end
- Sugar makes up the 3’ end (OH Group)
In which way does DNA Replication occur?
5’ to 3’
Summarize the steps of DNA Replication
- Split the parent strand to create the replication fork (replication bubble in prokaryotes)
- RNA Primer added
- DNA Polymerase III adds complimentary nucleotide strands in the 5’ to 3’ direction
- RNA Primers are replaced with DNA
Define semiconservative replication
One parent and one daughter strand of DNA
T/F: DNA replication is done at a single origin of replication
False; there are mltiple replication forks that work to get all the DNA
Important differences between RNA and DNA
DNA
- Deoxyribose (H)
- A-T
- Double Stranded
RNA
- Ribose (OH)
- A-U
- Single Stranded
What is transcription? Describe the process
DNA to RNA
- Split DNA and create mRNA transcript using RNA Polymerase
- mRNA leaves the nucleus/nucleoid region and heads to ribosome
What is translation? Describe the process
RNA to Protein
- mRNA attatches to ribosome
- tRNA brings in amino acids starting at AUG
- Creates peptide bonds between amino acids until stop codon is reached (UAA, UAG, UGA)
- the stop codon doesnt make a protein it just releases it for folding
Codon vs Anticodon
Codons are found on the mRNA strand and code for specific amino acids
Anticodons are found on the tRNA, are complementary to the mRNA strand, and allow it to bind and carry amino acids to the ribosome
What ultimately determines the phenotype
Proteins
Identify and describe the thee types of RNA
mRNA - Consists of codons that code for amino acids
tRNA - Transfers amino acids to the ribosome and contains the anticodon
rRNA - Forms the ribosome and functions to create proteins
What is the start codon and what protein does it make?
AUG - Methionine
What are the three stop codons?
UAG (u are gone)
UAA (u are away)
UGA (u go away)
What are the three major steps for transcription and translation decribed in lecture?
Initiation
Elongation
Termination
What enzyme directs transcription?
RNA Polymerase
The process of shifting the ribosome down the mRNA strand to synthesize amino acids
Translocation
T/F: More than one codon can exist for an amino acid. Explain
True; this allows for some mistakes in the process and still be okay
Which antibiotic drugs inhibit protein synthesis
Tetracycline, Aminoglycosides
Describe Recombination
An event in which one bacterium donates DNA to another bacterium.
- The end result is a strain different from the donor and the recepient
- The recipieint that contains and expresses genes that came from another organism is a RECOMBINANT
Vertical vs Horizontal Gene Transfer
Vertical - Between generations (parent to offspring)
Horizontal - Within the same generation (just a nearby cell not given through binary fission)
Identify (dont describe) the three types of horizontal gene transfers completed in class
Transduction
Conjugation
Transformation
Describe Transduction
Involves bacteriophage inserting DNA/RNA into the cell; while the viruses are reproduced some of them pick up nonviral, bacterial dna. This virus goes on to infect new cells, and inserts nonviral dna into another bacterial cell
Describe Conjugation
Bacterial sex involves the pilus that transfer of genetic infromation from plasmids
Describe Transformation
COMPETENT cells picks up small frgaments of DNA from the environment (dna gets into environment when a nearby one dies)
Define Mutation
Any change or alteration of the original sequence of DNA that is permanent and can be passed to offspring
Identify a negative and positive effect of mutations
Pos - Work to help generate antimicrobial agents
Neg - Antibiotic resistance
Wild vs Mutant Types
Wild - Original, nonmutated
Mutant - Mutated
Spontaneous vs induced mutations
Provide an example
Spontaneous - Issues in DNA replication
Induced - Result from the exposure to a mutagen (photons from UV light)
TYPES OF MUTATIONS:
Silent
Codes for the same protein and has no effect on the cell or organism
TYPES OF MUTATIONS:
Nonsense
Codes for a stop codon
TYPES OF MUTATIONS:
Conservative Missense
Different proteins but conserves some of the same properties and acts similarly to the original protein
TYPES OF MUTATIONS:
Non Conservative Missense
Different protein that does not conserve some of the same properties of the original protein
TYPES OF MUTATIONS:
Frameshift
One or more bases are insterted or deleted that alters the reading frame of the RNA that nearly always leads to nonfunctional proteins
Point Mutations
Small mutations that affect a single base on a gene
Lethal vs Neutral mutations
Lethal - Leads to cell dysfunction or death
Neutral - Has no adverse or helpful changes to the cell
T/F: A spontaneuous mutation arises from exposure to chemicals or physical agents
False; this is an example of an induced mutation
Which mutation type results in a stop codon
Nonsense
Which mutation type nearly always results in a nonfunctional protein
Frameshift
T/F: Mutations are always harmful to organisms
FALSE; not always
